Understanding the way society works and the rules that you have to play by is a fact of life that all of our characters have to deal with. Heck, it's something we have to deal with every day, too, isn't it? Society tells us what we can and can't do. The rules of society sway the decisions that our characters make; everyone worries about what others will think about them. Gwendolen would rather marry Grandcourt for money than have to work as a governess and be looked down upon by others. The Arrowpoints object to Catherine marrying Klesmer because he's not in the same "class" as they are. Lydia Glasher has to live at Gadsmere with her kids where nobody knows her scandalous story. In Daniel Deronda, society is a pretty tangled web; imagine how much trickier it would be if they were all on Facebook.
Daniel Deronda gives us the impressions that society is on the brink of change; people are becoming more accepting of people from all different walks of life.
Daniel Deronda shows us that society is fixed and rigid.